Isotropic zero CTE reinforced composite materials

Abstract

A reinforced composite material, having isotropic thermal expansion properties and a low coefficient of thermal expansion over at least the temperature range of from about 0° C. to at least about 150° C., which composite material comprises in combination a first continuous phase comprising a three dimensional preformed bonded powder material reinforcement, including a bonding agent, and in which the bonded powder material is chosen from the group consisting of zirconium tungstate, hafnium tungstate, zirconium hafnium tungstate, and mixtures of zirconium tungstate and hafnium tungstate, and a second continuous phase matrix material chosen from the group consisting of aluminium, aluminium alloys in which aluminium is the major component, magnesium, magnesium alloys in which magnesium is the major component, titanium, titanium alloys in which titanium is the major component, engineering thermoplastics and engineering thermoplastics containing a conventional solid filler.

Description

[0001] This is a Continuation-in-part of U.S. patent application, Ser. No. 10 / 921,328 filed Aug. 19, 2004, which is a Continuation-in-part of U.S. patent application, Ser. No. 10 / 147,460 filed May 17, 2002.FIELD OF THE INVENTION [0002] This invention relates to reinforced composite materials in which the two continuous phases comprising respectively the matrix and the reinforcing material used to fabricate the composite material cooperate to provide a composite material having a zero, or near zero, coefficient of thermal expansion (CTE) in the conventional mutually perpendicular X, Y and Z directions. The reinforced composite materials of this invention are thus described as being isotropic with respect to their thermally induced expansion behaviour. SUMMARY OF INVENTION [0003] In the field of low CTE materials there are several accepted units used to express CTE values; in what follows, with the exception of the discussion of the prior art, all CTE values are all expressed 10−6 / 0K,...

AI Technical Summary

Benefits of technology

[0007] Two current major applications of low CTE materials are in thermal management hardware such as heat sinks and the like for solid state electronic devices, and in signal transmission antenna structures for both transmitting and receiving complex signals in microgravity environments. Thermal management is an essential feature of the design of solid state electronic devices, and dimensional thermal stability is extremely important for antennas used in microgravity applications in space which are exposed to a relatively wide temperature range; relatively small changes in dimensions can radically alter the performance of an antenna.

Problems solved by technology

For many applications, Invar has three significant disadvantages: it is an expensive alloy to make, it is expensive to machine or fabricate into complex shapes, and it is relatively heavy (the density of Invar is 8.1 g / cc), compared either to alloys based on light metals such as magnesium and aluminium, to the so-called engineering plastics, or to reinforced composite plastic materials comprising a polymer matrix together with a reinforcement.